# -*- coding: utf-8 -*- #
# Copyright 2017 Google LLC. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#    http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""Code that's shared between multiple networks subcommands."""

from __future__ import absolute_import
from __future__ import division
from __future__ import unicode_literals

from googlecloudsdk.calliope import parser_errors


RANGE_HELP_TEXT = """\
    Specifies the IPv4 address range of legacy mode networks. The range
    must be specified in CIDR format:
    [](http://en.wikipedia.org/wiki/Classless_Inter-Domain_Routing)

    This flag only works if mode is
    [legacy](https://cloud.google.com/compute/docs/vpc/legacy).

    Using legacy networks is **DEPRECATED**, given that many newer Google
    Cloud Platform features are not supported on legacy networks. Please be
    advised that legacy networks may not be supported in the future.
    """


_RANGE_NON_LEGACY_MODE_ERROR = (
    '--range can only be used with --subnet-mode=legacy.')

_BGP_ROUTING_MODE_CHOICES = {
    'global': 'Cloud Routers in this network advertise subnetworks from all '
              'regions to their BGP peers, and program instances in all '
              'regions with the router\'s best learned BGP routes.',
    'regional': 'Cloud Routers in this network advertise subnetworks from '
                'their local region only to their BGP peers, and program '
                'instances in their local region only with the router\'s best '
                'learned BGP routes.',
}

_CREATE_SUBNET_MODE_CHOICES = {
    'auto': 'Subnets are created automatically.  This is the recommended '
            'selection.',
    'custom': 'Create subnets manually.',
    'legacy':
        '[Deprecated] Create an old style network that has a range and cannot '
        'have subnets.  This is not recommended for new networks.',
}


def AddCreateBaseArgs(parser):
  """Adds common arguments for creating a network."""

  parser.add_argument(
      '--description',
      help='An optional, textual description for the network.')

  parser.add_argument('--range', help=RANGE_HELP_TEXT)


def AddCreateSubnetModeArg(parser):
  """Adds the --subnet-mode flag."""
  parser.add_argument(
      '--subnet-mode',
      choices=_CREATE_SUBNET_MODE_CHOICES,
      type=lambda mode: mode.lower(),
      metavar='MODE',
      help="""The subnet mode of the network. If not specified, defaults to
              AUTO.""")


def AddMtuArg(parser):
  """Adds the --mtu flag."""
  parser.add_argument(
      '--mtu',
      type=int,
      help="""Maximum transmission unit (MTU) is the size of the largest
              IP packet that can be transmitted on this network. Default value
              is 1460 bytes, and the maximum is 1500 bytes. The MTU advertised
              via DHCP to all instances attached to this network.""")


def AddCreateBgpRoutingModeArg(parser):
  """Adds the --bgp-routing-mode flag."""
  parser.add_argument(
      '--bgp-routing-mode',
      choices=_BGP_ROUTING_MODE_CHOICES,
      default='regional',
      type=lambda mode: mode.lower(),
      metavar='MODE',
      help="""The BGP routing mode for this network. If not specified, defaults
              to regional.""")


def AddUpdateArgs(parser):
  """Adds arguments for updating a network."""

  mode_args = parser.add_mutually_exclusive_group(required=False)

  mode_args.add_argument(
      '--switch-to-custom-subnet-mode',
      action='store_true',
      help="""Switch to custom subnet mode. This action cannot be undone.""")

  mode_args.add_argument(
      '--bgp-routing-mode',
      choices=_BGP_ROUTING_MODE_CHOICES,
      type=lambda mode: mode.lower(),
      metavar='MODE',
      help="""The target BGP routing mode for this network.""")

  AddMtuArg(parser)


def AddUpdateArgsAlpha(parser):
  """Adds alpha arguments for updating a network."""

  AddUpdateArgs(parser)


def CheckRangeLegacyModeOrRaise(args):
  """Checks for range being used with incompatible mode and raises an error."""
  if args.IsSpecified('range') and args.IsSpecified(
      'subnet_mode') and args.subnet_mode != 'legacy':
    raise parser_errors.ArgumentError(_RANGE_NON_LEGACY_MODE_ERROR)
